This invention relates to a tape cassette including upper and lower halves secured to each other to define a space for receipt of a pair of tape reels and, more particularly, to a tape cassette having a window opening provided in the upper half above one of the tape reels and a transparent window plate covering the window opening, the window plate being produced through a molding process using a gate for spouting a fused synthetic resin into a molding cavity.
Generally, tape cassettes include upper and lower halves secured to each other to define a space containing a pair of tape reels. In order to provide a visual indication of rotation of the tape reels, the upper half has a semicircular window opening above one of the tape reels, the window opening being covered with a transparent window plate having a semicircular shape conforming to the window opening. It is normal practice to produce such a transparent window plate through a molding process using a gate through which a fused synthetic resin is spouted into a molding cavity. Through such a molding process, however, a gate mark is made on the produced window plate near its center, degrading the appearance. Another disadvantage with conventional tape cassettes is that some technique is required in molding a semicircular window plate having acute-angled corners made by the arc and chord of the semicircular window plate. In addition, a great stress concentration occurs at the acute-angled corners during the molding process, reducing the service life of the produced window plate.